W&N set of 4 brushes (0, 1, 2, 3) in the
UK is GBP 34.50
http://www.artsupplies.co.uk/item-winsor-&-newton-series-7-brush-set-(4).htm
Ichiban set of those 4 brushes (00, 0, 1, 2) is GBP 30 (non-early bird)
Not that far apart. W&N has the "guaranteed" quality and no waiting for it to be shipped. Ichiban has the fancy storage stuff, possibly stretch goals and the warm "kickstarter-support" feeling.
You can also find them cheap on ebay apparantly.
I backed the brushes kickstarter and I was unimpressed. The only significant advantage I saw was that I effectively got 14 brushes for £25 so I wasn't exactly going to complain. I think the thing with it is I can walk into town and buy a
GW brush set, or a W&N set and have them today. I can check everythings alright with them and both will happily replace any defects straight away.
Oh, and the file sets a joke. Other companies sell the same thing for cheaper without branding.